The industrial production of wooden frames, and particularly of rectangular frames for paintings, photographs, mirrors and others, already uses automatic assembling machines which, starting from four strips cut at 45xc2x0 at both ends, pick up the strips and place them to join in pairs, at an angle, and be coupled by way of appropriate generally V-shaped steel staples which are inserted pneumatically astride the joining lines.
However, mostly due to the incorrect length of some of the strips, the joints are sometimes imperfect because the ends of the strips arranged adjacent at an angle fail to mutually coincide so to form the corners of the frame.
The aim of the present invention is to ensure in any circumstance, in machines that form rectangular frames, that the ends of the strips automatically coincide perfectly in all angled joints even if their length is imperfect.
This aim has been fully achieved with a particular device which can be used on various machines, already used to form rectangular frames. For the purpose of merely showing its operation and advantages, said device is shown installed, in the accompanying drawings, in a machine devised by the same Applicant and disclosed in U.S. Ser. No. 09/546,435 of Apr. 10, 2000.
Indeed to facilitate reference to the above patent and aid comprehension of the improved machine as a whole, in the accompanying drawings the same reference numerals are used to designate corresponding parts or elements.